Grinding wheel feeding mechanism



Feb. 1, 1949.

C. G. FLYGARE Er AL GRINDING WHEEL FEEDING MECHANISM Filed Aug. 17, 1945.

l l k I l r 1| 0 @n/fou EARL G.FL YGARE HOMER L..5WAINEY WMw-wn W Patented Feb. 1, 1949 UNITED STATES PATENT ,orri'ca Gl tINDING WHEEL FEEDING MECHANISM v Carl G. Flygare, Worcester, Mass., and Homer L. Swainey, Shaker Heights, Ohio, asslgnors to Norton Company, Worcester,"Mass., a corporation of Massachusetts Application August 11, 1945, Serial No. 611,144

The invention relates to grinding machines,

and more particularly to a control mechanism for a hydraulically operated grinding wheel feeding mechanism.

One object of the invention is to provide a simple and thoroughly practical hydraulically operated grinding wheel feeding mechanism for grinding machines. Another object of the invention is to provide a wheel feed controlling mechanism which is arranged so thatthe grinding wheel may be fed rapidly so as to move into operative engagement with the work, then to be reduced to a slow predetermined grinding feed. Another object of the invention is to provide a hydraulic piston and cylinder to move the wheel slide rapidly to and from an operative position combined with adash pot feed regulator to slow down the rapid approaching movement oi-the grinding wheel to a slow predetermined grinding feed. Another object of the invention is to provide means for positively returning the dash pot piston to an inoperative position and thereby positively fill the dash pot cylinder chambers with iiuid during the idle stroke of the grinding wheel slide so that the dash pot chambers are filled, ready for the next feeding operation.

' another object of the invention is to provide a single control valve which serves to control the admission of fluid to and from the hydraulic feeding cylinder when in a position to cause a movement of' the grinding wheel to an inoperative position and which also serves to convey fluid under pressure from the fluid pump into the dash pot cylinder chambers to return the dash pot pistons to an inoperative position and rapidly fill the dash pot cylinder chambers with fluid for the next grinding operation. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations oi. elements; and arrangements of parts, as will be exemplifled in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawing in which is shown one of various possible embodiments of ,the mechanical features of this invention, the

drawings comprising a base iii which supports a longitudinally movable work supporting table 4 Claims. (01. 51165) Ii on the usual flat way l2 and V-way It so that the table II may be readily moved lengthwise of the base it to position a work piecein the desired operative relation with a grinding wheel.

. The table Ii serves as a support for a headstock it having a headstock center It and a footstock (not shown) rotatably to support a work piece. to be ground.

The base ill also supports a transversely movable wheel slide on the usual well known v-way and fiat way (not shown). The wheel slide 20 is provided with a rotatable grinding wheel which is mounted on one end of a wheel spindle 22. The wheel spindle 22 is journalled in suitable bearings (not shown) in the wheel slide 29. A driving mechanism is provided for driving the grinding wheel 2i comprising an electric motor 23 mounted on the upper portion of the wheel slide 20. The motor 23 is provided with an armature haft it having a multiv-groove pulley 25 mounted on its outer end. The multi-V-groove pulley 25 is connected by multiple V-belts 26 with a multi-V-groove pulley it which is mounted on the outer end of the wheel spindle it.

A feeding mechanism is provided for adjusting the position of the wheel slide it transversely relative to thebase it comprising a half nut 30 depending from the under side of the wheel slide it. The half nut 3t meshes with a rotatable feed screw ti which is rotatably journalled in suitable bearings in the base it. The right-hand end of the feed screw it is rotatably journalled in a slidably keyed sleeve 32 which is slidably mounted in a cylindrically shaped aperture 33 which is fixed relative to the base it. The left-hand end of the feed screw is slidably keyed within .a hollow end portion 3d of a rotatable shaft 35. The shaft 35 is journalled in a bearing it which is fixed relative to the machine base ill. The other end of the shaft 35 is ioumalled in a suitable bearing (not shown) which is fixed relative to the base iii. feed wheel 36 having the usual and well known micrometer adjusting mechanism ii is mounted on the front of the machine base and is operatively connected to rotate a gear it which is mounted on the outer end of the shaft 35. It

will be readily apparent from the foregoing dis closure that a rotary motion of the feed wheel.

36 will be transmitted to rotate the feed screw 3i and thereby transmit a transverse movement to the wheel slide 20 and the grinding wheel ii.

In order to provide a rapid approaching and receding movement of the grinding wheel; a

'A suitable manually operable for rapidly moving the wheel slide 28 to and from an operative position comprising a hydraulic cylinder 48 which is fixed relative to the base 8. The

cylinder 48 contains a slidably mounted piston 4| which is connected to a double end piston rod 82. The double end piston rod 42 projects through the cylinder heads at both ends of the cylinder 48. The left-hand end of the piston rod 42 is connected to the slidably mounted sleeve 82. The piston rod 42 is preferably arranged in axial alignment with the feed screw 8|. When fluid under pressure is admitted through a pipe 88 into a cylinder chamber 44, the piston 4| will be moved toward the right to move the wheel slide 28 and grinding wheel 2| also in a direction toward the right to an inoperative position. During this movement fluid within a cylinder chamber 45 is exhausted through a pipe 48.

A hydraulic control system is provided for supplying actuating fluid under pressure to the cylinder 48. This mechanism may comprise a motor driven fluid pump 58 which draws fluid through a pipe 5i from a box-like reservoir 52 which, as illustrated, is formed within the base I8 I of the machine. The pump 58 forces fluid under pressure through a pipe'53 to a control valve 54. A variable pressure relief valve 55 is connected in the pipe line 53 to facilitate maintaining the desired operating pressure in the hydraulic system. The relief valve 55 serves to return excess fluid-under'pressure directly to the reservoir 52 and thereby to maintain uniform pressure within the hydraulic system.

The control valve 54 is preferably a piston type control valve comprising a valve stem 58 which is provided with a plurality of integrall formed valve pistons 51, 58. 59, 88 and 5|. A manually operable control lever 82 is pivotally supported on a stud 65 which is supported by a bracket 84 fixed on the front of the machine base Ill. The control lever 82- is connected by means of a pin 85 with a slot 88 formed in the valve stem 58. By manipulation of thecontrol lever 82, the valve stem 58 may be shifted from one extreme position to the other. In the full line position illustrated in the drawing, the valve stem 58 is shown inits rearward or right-hand end position to maintain the wheel slide 28 and grinding wheel 2| in a rearward or inoperative position. When it is desired to cause a forward feeding movement of 'the grinding wheel 2|, the control lever 82 is moved in a counterclockwise direction into broken line position 82a to shift the valve stem 56 into its extreme left-hand position.

Fluid under pressure passing through the'pipe 53 enters a valve chamber I8 formed between the 4 42 is moved in a counterclockwise direction to position the valve stem 58 in its extreme left-hand end position. in which position fluid under pressure entering the valve chamber 18 will pass through the pipe 48 into the cylinder chamber 45 to cause the piston 4|, the wheel slide 28, and the grinding wheel 2| to move toward the left rapidly to approach the work piece to be ground. During the forward feeding movement, fluid within the cylinder chamber 44 exhausts through the pipe 48 into a valve chamber 15 located between the valve pistons 88 and 8| and pass outwardly through the exhaust pipe 13 and the throttle valve 14 into the reservoir 52. It will thus be seen that the throttle valve 14 may be adjusted to control the rate ofthe rapid approaching and rapid receding movement of the grinding wheel 2|.

In order to slow down the rapid approaching movement of the grinding wheel 2| to a slower predetermined grinding feed, a dash pot feed regulator 88 is provided comprising a pair of dash pot cylinders 8| and 82 which are arranged on diametrically opposite sides of the rearwardly extending portion of the piston rod 42. The dash pot cylinders 8| and 82 are provided with dash pot pistons 83 and 84, respectively. Compression springs 85 and 86 may be provided normally to urge the dash pot pistons 83 and 84 in a direction toward the right.

The rearward or right-hand end of the piston rod 42 is provided with a threaded portion 81 having an adjustable collar 88 supported thereon. When the piston 4| is moved toward the 'left rapidly to position the grinding wheel 2|, the rapid movement continues until the collar 88 engages the left-hand end of a sleeve 88 which is supported on the piston rod 42. The sleeve 88 is provided with a flanged portion 88 which is fixedly mounted on the sleeve 89 or may be formed integral therewith if desired. The flange 88 is arranged in operative engagement with the righthand ends of both of the dash pot pistons 83 and 84, respectively. As the collar 88 engages the sleeve 88, continued movement of the piston 4| causes the flange 98 to start movement of the I dash pot pistons 88 and 84 toward the left. This valve pistons 59 and 88 and in the position illusthrough an exhaust pipe I8 into the reservoir 52.

A manually operable throttle valve I4 is provided in the pipe line 18 to facilitate controlling the rate ofexhaust of fluid from the cylinder chamber 45 and thereby to control the rate of movement of the wheel slide 28 and the grinding wheel 2| to an inoperative position.

When it is desired to initiate a forward feeding movement of the grinding wheel 2|, the lever movement serves to force fluidout of the dash pot cylinders 8| and 82. By controlling the exhaust of fluid from the dash pot cylinders 8i and 82 by means of a needle valve 8|, the rapid approaching movement of the grinding wheel 2| may be slowed down to the desired and predetermined grinding feed. Fluid exhausting through the needle valve 8| passes through a pipe 92 and returns to the reservoir 52. An adjustably mounted stop screw 83 is provided to determine the right-hand end-position of the flange 88 and the dash pot pistons '88 and 84.

It is desirable to provide a suitable meansfor rapidly returning the dash pot pistons and 84 to their rearward or inoperative positions when the grinding wheel 2| is moved to an inoperative position after a grinding operation has been completed. As illustrated in the drawings, fluid under pressure from pump 58 passing through the pipe 58 may also pass through'a pipe 85, through a throttle valve 88, through a-variable pressure control valve 81, into a valve chamber 98 located between the valve pistons 51 and 88.

into the position illustrated, fluid will be admitted 6 of the wheel slide 28 and the grinding wheel 2|. The rapid approaching movement continues until the grinding wheel 2| is about to engage the surface of the work to be ground, at which point the fill the dash pot cylinder chambers 8| and 82,v

ready for the next infeeding movement. The variable pressure control valve 9'! is provided so that if desired the pressure applied to return the dash pot pistons 88 and 84 to their inoperativeposition may be at a lower'pressure which is independent of the pressure within the .main hydraulic system.

In certain grinding operations, it is desirable to feed the. grinding wheel 2| into the work to reduce it to approximate size, after which the feeding movement of the grinding: wheel 2| is further slowed down or reduced to an extremely fine feed just prior to positively stopping the infeed by engagement of the stop collar I86 with the stop surface I04. This may be accomplished by providing an adjustable throttle valve I88 in the pipe line |ll2 which is arranged to control the exhaust of fluid from the dash pot cylinders Bi and 82 after the port leading to the needle valve 9| is closed by the forward movement of the dash pot piston 83. It will be readily apparent from the foregoing disclosure that the valve I82 may be entirely closed, in which case the needle valve 9| will control the entire infeed of the grinding wheel or, when desired the throttle valve I83 may be opened to the desired extent so that after closing Of the port leading to the needle valve 8|, the valve I03 will control the exhaust of fluid from the dash pot cylinders 8| and 82, thus facilitating an extremely fine precise feed movement of the grinding wheel at 2|.

It will be readily apparent that when the lever 82 is'shifted in a counterclockwise direction into "collar 88 engages the sleeve 88, after which continued movement of the piston 4| is retarded by the dash pot pistons 88 and 84, forcing fluid from .the dash ,pot cylinders 8| and 82 out through the needle' valve 8| which controls the rate of the grinding feed until the port leading to valve M is closed by dash pot piston 83. The forward grinding feed continues under the control of throttle valve-|08 until a positive stop collar I88 carried by the sleeve 89 engages a positive stop surface I formed on an end cap I080! the dash pct 88. After the work-has been ground to the desired size, the control lever 82 is again shifted in a clockwise direction into the full line position illustrated in the drawing so that fluid under' pressure is passed through the pipe 48 into the cylinder chamber 44 to move the piston 4| rapidly toward the right into the position illustrated, thus rapidly moving the wheel slide 20 and grinding wheel 2| to an inoperative position. At the same time the valve stem 5'8 is shifted into the position illustrated, fluid under pressure is passed through the pipe 88 into the dash pot cylinder chambers 8| and 82 rapidly to return'the dash pot pistons 83 and 84 into their extreme righthand end positions and also rapidly to fill the dash pot cylinders Bi and 82 ready for the next infeeding movement.

It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodi'ments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

position 82a to initiate a grinding feed, the valve ton and cylinder to s? ow down the rapid approachwill rapidly cause .an approaching movement of the grinding wheel 20 until the dash pot pistons 83 and 84 start movement. When the dash pot pistons 83 and 88 start moving, fluid within the dash pot cylinders 8| and 82 is exhausted through the needle valve 9|, thus retarding the rapid apinto its left-hand end position. This movement of the valve stem serves to trap fluid withinthe dash pot cylinders 8| and 82 and at the same time serves to pass fluid through the pipe 48 into the cylinder chamber 45 to move the piston 4| rapidly toward the left to cause a rapid approaching movement I ing movement to a predetermined relatively slow grinding feed, a control valve to control the admission of fluid to and exhaust of fluid from said hydraulic cylinder, and means including a pipe directly connecting the control valve with the dash pot cylinder to admit fluid under pressure directly from the pump to the dash pot cylinder during movement of the wheel slide to an inoperative position positively to'return the dash pot piston to an inoperative position so as to rapidy fill the dash pot cylinder for the next grinding operation.

2. In a grinding machine having a base, a transversely movable grinding wheel slide, a rotatable grinding wheel on said slide, a hydraulic piston and cylinder to move said slide rapidly toward and from an operative position, a dash pot feed regulator including a dash pot piston and'cylinder to slow down the rapid approaching movement to a predetermined relatively slow grinding feed, a control valve to control the admission of fluid to and exhaust of fluid from said hydraulic cylinder, and means including a pipe directly connecting the control valve aware-rwith the dash pot cylinder, said control valve-be-. ing arranged to admit fluid under pressure directly from the pump throughsaid pipe'to the dash pot cylinder positively to return the dash pot piston to an inoperative position so as to rapidly flll the dash pot cylinder when the control valve is shifted to cause movement of the grinding wheel to an inoperative position.

3. In a grinding machine having a base, a transversely movable grinding wheel" slide. a rotatable grinding wheel on said slide, a hydraulic piston and cylinder to move said slide rapidly toward and from an operative position, means including a fluid pump to supply fluid under pressure, a dash pot feed regulator including a dash pot piston and cylinder'to slow-down the rapid approaching movement to a predetermined relatively slow grinding feed, an adjustable needle valve to control the exhaust of fluid from the dash pot cylinder to regulate the grinding feed, a control valve to control the admission of fluid to and exhaust of fluid from said hydraulic cylinder, and a pipe connecting said control valve directly with the dash pot cylinder, said control valve being arranged simultaneously to admit fluid under pressure to said hydraulic 7 cylinderto cause a rearward movement of the grinding wheel to an inoperative position and to admit fluid under pressure directly fro'mj'the pump through said control valve and pipe to the dash pot cylinder positively to return the dash pot piston to an inoperative position and to 1111 the dash pot cylinder for the next grinding operation.

'4. In a grinding machine having a base, a transversely movable grinding wheel slide, a rotatable grindin wheel on said slide, a hydraulic piston and cylinder to move said slide a. rapidly toward and from an operative position, means including a fluid pumpto supply fluid under pressure, a dash pot feed regulator including a dash pot piston and cylinder to slow down the rapid approaching movement to a predetermined slow grinding feed. an adjustable needle valve t0.9,0!ii7i01 the exhaust of fluid from said dash potlcylinder so as to regulate said grinding feed, a control valve to control the admission 0! fluid to and exhaust or fluid from said hydraulic cylinder, a pipeconnecting said control valve directly with said dash pot cylinder, said control valve being arranged when in a forward feeding position to prevent exhaust of fluid from said dash pot cylinder except through said needle valve, said control valve having an independent valve chamber which is arranged to admit fluid under pressure directly from the pump and control valve to said dash pot cylinder positively to return the dash pot piston-when the control valve is in a rearward feeding position to move the grinding wheel to an inoperative position so as positivelyto flllthe dash pot cylinder for the next grinding operatio CARL G. FLYGARE,

HOMER L. SWAINEY.

REFERENCES crrEn ,The following references are of record in the flle; of this patent: UNITEDSTATES PATENTS Number Date Silven et al Jan. 21, 1941 

